This invention relates to fluid control valves and more particularly to three part valves and methods.
Fluid control valves to direct the flow of fluid, liquid or gas, are well known, and it has long been desirable to provide a valve capable of performing multiple functions. The typical multi-function fluid valve is of the linear displacement spool type consisting of a spool with several fluid inlet and outlet ports, each having a seating surface. Such known valves are capable of performing multiple functions by simultaneously or sequentially establishing various fluid flow paths through the spool. However, the number of functions performed by such valves is limited by the complexity of the valve construction and the physical size of the valve. Additionally, such valves requires a large number of precisely machined parts and seals, and maintenance and repair is generally costly.
Rotary valves are also well known and have fewer moving parts than spool valves. Typically, a rotor having a U-shaped passageway is rotated with respect to a ported surface of a valve body to interconnect various ports of the valve body through the rotor. Such valves may be two function valves, i.e., they may selectively connect one input port to one of two output ports, or vice versa. More complex rotary valves can simultaneously route more than a single fluid stream to various destinations by use of a more than one U-shaped passageway in the rotor.
Because rotary valves establish a flow path by aligning the channel of the rotor with selected ports of the stationary member and did not have cut-off valves within the rotor passageways, care had to be taken to ensure that non-selected ports were not "inadvertently" connected by rotation of the rotor relative to the stationary member. This limited the use of such valves to multiple functions carried out in a predetermined sequence.
The present invention obviates the need for use of a separate cutoff valve to prevent "inadvertent" flow paths from being establish by using a rotary valve having two movable members. Additionally, the use of two movable members increases the number of functions that can be performed by the valve. In the present invention, the first member selects the fluid function to be executed by aligning non-connected conduits with the selected ports. The second member can then execute the selected function by connecting the two conduits thereby establishing a fluid flow path between the selected ports through the first and second member.
Accordingly, it is an object of the present invention to obviate many of the limitations of known valves and to provide a novel multiple function fluid valve and method.
It is another object of the present invention to provide a novel valve and method capable of selecting one of several functions and then selectively executing the selected function.
It is another object of the present invention to provide a novel valve and method of connecting selected ports to establish a fluid communication path.
It is yet another object of the present invention to provide a novel plural function valve and method having separate moving members to select and then execute the desired function.
It is still another object of the present invention to provide a novel valve and method for performing complex fluid functions.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.